Anticipate heavy loads. Get layout and weights from end user and Use heavy loads. Compute weights. Do not forget to account for UPS since they can be serious loading. I would use 150 PSF as minimum and go from there. Add 2000 pound concentrated load. Also, insure he raised floor system, if any, is also capable of supporting the live loads.
One reference that I use, it states requires 150 PSF for Telephone exchange rooms and central computer. The reference is UFC 3-301-01 ( STRUCTURAL ENGINEERING).
Regards,
Lutfi